Ten years ago, Indian economist and politician Jairam Ramesh coined a word that captivated pundits and investors: "Chindia."

The idea that China and India might join forces, to cooperate as much as they compete, was both seductive and fleeting. Observers were heartened by promises from then-Chinese President Hu Jintao and Indian Prime Minister Manmohan Singh to enact sweeping internal reforms and embrace regional cooperation — neither of which happened. The leaders of the world's most populous nations turned inward. Their domestic problems festered.

Now that Beijing and New Delhi are in the hands of Xi Jinping and Narendra Modi, both self-described reformers, could Chindia finally come to fruition as a force for mutual prosperity?